As will be appreciated, oil and natural gas have a profound effect on modern economies and societies. For instance, oil and natural gas are used for fuel in a wide variety of vehicles, such as cars, airplanes, boats, and the like, in addition to manufacturing an astonishing array of everyday products. In order to meet the demand for such natural resources, companies often invest significant amounts of time and money in searching for and extracting oil, natural gas, and other subterranean resources from the earth. Particularly, once a desired resource is discovered below the surface of the earth, drilling and production systems are often employed to access and extract the resource. These systems may be located onshore or offshore depending on the location of a desired resource.
In offshore operations, oil platforms typically support risers that extend from one or more wellheads or structures on the seabed to the platform on the sea surface. Such systems generally include a wellhead assembly to extract resources through, in which these wellhead assemblies include a wide variety of components, such as various casings, valves, fluid conduits, and the like, to control drilling and/or extraction operations. The risers connect the subsea well with the platform to protect the fluid integrity of the well and to provide a fluid conduit to and from the wellbore. During drilling operations, a drilling riser is used to maintain fluid integrity of the well. After drilling is completed, a production riser may be installed.
For example, in a subsea well, a riser made of up riser sections may extend from the seafloor up to a rig on the surface of the sea. A typical riser section may include a flanged assembly formed from steel on each end, and the riser may perform multiple functions. In addition to transporting drilling fluid into the well, the riser may provide pipes to allow drilling fluids, mud, and cuttings to flow up from the well. Further, once production begins, a riser may be used to transport production fluids from the well to the rig or other location for storage or refinement.
As subsea wells are placed in deeper subsea locations (e.g., 10,000 to 12,000 ft.), conventional risers may become difficult to install and operate. Because of the tension and pressure load at such depths, typical riser joints are designed to be heavier to withstand this increased tension and pressure. However, such heavier risers may exceed the derrick capacity or the deck load of the rig supporting the riser. For example, increasing the pressure capacity of the riser joints within a riser system may increase the weight of the riser system by about 1,000,000 lbs (about 453,600 kg) or more. Additionally, longer risers may require increased tension to ensure stability and rigidity of the riser. As such, reducing the weight of risers and accompanying equipment remains a priority to increase the efficiency and safety and reduce the cost of subsea equipment.